Finger vein verification using Occurrence Probability Matrix (OPM)

We found that the discrepancy between different finger vein templates of the same finger affects the identification results more seriously than the similarity of templates of different fingers does. Some areas on templates have stable values while some other areas are variable. We propose the Occurrence Probability Matrix (OPM), which is a property of a finger, to define the stability. When matching two templates using OPM, the areas of higher stability make more contribution to the result and those of lower stability make less contribution. In this way, OPM can enhance the similarity of templates of the same finger and drop off the influence of the unsteady areas. In a finger vein verification system running for a long time, we can get enough templates of every finger to generate an effective OPM. But it does not mean that using more templates can get a better OPM. So, we fatherly propose a strategy to select typical templates purposely from all templates of a finger to calculate the OPM. Experimental results show that by simply using OPM calculated from all existing templates, the EER of the system is reduced from 9.8% to 7.6%. And by using the OPM calculated from selected typical templates by our strategy, the EER of the system is further reduced from 7.6% to 3.1%.